This invention relates generally to a gas absorption refrigerator, such as typically equips a recreational vehicle (RV), boat or a trailer home. More particularly, the invention relates to a gas absorption refrigerator with increased cooling power compared with a conventional RV refrigerator without extending the refrigerator cabinet in an upward direction. This cooperative arrangement of vehicle space and refrigerator components enables the refrigerator cold compartment to be enlarged in a horizontal direction.
Recreational vehicles are commonly equipped with refrigerators for cooling and preserving food and drinks. Such refrigerators are usually conventional gas absorption-type refrigerators which use a heat source to effect refrigeration. Absorption refrigerators are favored in vehicles such as recreational vehicles because a compressor is not required and the heat generator can be either an electrical resistance heater or a gas heater and allow selection between the heat sources. The gas heater can be fueled by propane gas which is usually carried on a recreational vehicle.
In an absorption refrigerator the heat generator heats a solution of a refrigerant and an absorbent. Heating the solution releases a portion of the refrigerant from the solution in the form of a vapor. The refrigerant vapor is condensed in a cooling condenser. The refrigerant is boiled in the evaporator, which removes heat from the insulated compartment. The refrigerant vapor is combined back into the solution in the absorber and the combined solution is directed back to the generator.
It is well known in the art that absorption refrigeration units without special provisions cannot function when significantly inclined from the vertical, typically above 3.degree., due to the units' dependence on gravity and buoyancy to cause the circulation of working fluids in the required thermodynamic cycles. This is a particular problem for RV and other mobile refrigerators as the vehicle may not be level when in transit or parked. It is taught in U.S. Pat. Nos. 3,775,996; 3,802,219; 3,851,497 and 4,458,504 that it is desirable to incline the condenser, evaporator and absorber at significantly higher angles, between 10.degree. and 20.degree., to allow function of the refrigerator at higher angles of inclination. This solution has a particular disadvantage, however, because the vertical positioning of the components of the system is critical and long straight sections of piping angled across the width of the refrigerator may cause a given component to consume too much of the available cabinet height to allow proper vertical positioning of other components. The problem is especially acute when the available vertical height for the cabinet is restricted, even to the point of not allowing the normal angle of piping inclination in a short cabinet. The aforementioned patents teach solutions to this problem by specially configuring the condenser and absorber with shorter angled runs of piping in complex chevron shaped arrangements.
A gas absorption refrigerator of limited cabinet height has the additional problem that the height of the generator is restricted since it must, by necessity, be located vertically on the cabinet below the condenser. For a given heat input, the liquid and gas pressures created by the generator are partially determined by the height of the generator column. If the overall length of the condenser, evaporator or absorber is disproportionately long relative to the height of the generator or if the fluid flow path is unduly convoluted or restricted, the fluid flow is insufficient for efficient heat transfer and the cooling power of the refrigerator is reduced.